Ethernet Network Name Error

Hi folks, 

new to the eero community and a relative network novice. I’ve just setup my new eero network with 3 eeros connected to a Plusnet Hub One Sagecom router. All wireless devices setup no problem to network ABC, but I have a number of Ethernet connected devices which are proving troublesome. Anything connected via Ethernet is showing as connected to my original Plusnet network name XYZ with a 2 suffixed on the end of the network name. I have tried connecting via Ethernet directly to my gateway and to other eeros on the network, but the same result in each scenario.

There is inconsistency in whether the Ethernet devices show up in the eero app or not. This is particularly challenging for my Sonos devices, for which I prefer an Ethernet connection to one device for network stability. 
 

I’ve power cycled all devices and removed all Ethernet devices, starting with a single device connected directly to the gateway but still the same issue  

is this a known issue, or have I done something wrong during setup? Thanks in advance for any advice or pointers

Dan